Electrostatically shielded transformer coil windings and method of making the same



Nov. 24, 931.

M .Wilmer Let-d] w. J. LEIDY 1,833,221 ELECTROSTATICALLY SHIELDED TRANSFORMER COIL WINDINGS AND METHOD OF MAKING THE SAME F'l a n 30 1929 2 Sheets-Sheet 2 1 Nov. 24, 1931.

40 ing individual shields to a plurality of elecwanna a.

Patented Nov. 24, 1931 "U ITED STATES PATENT OFFICE.

LEIDY, OF CHICAGO, ILLINOIS, ASSIGNOR TO CHICAGO TRANSFORHLER 00R- ZPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS ELEGTROSTATIOALLY SHIELDED TRANSFORMER COILWIN'DINGS AND METHOD 0].

' MAKING THE SAME Application filed December 30, 1929. Serial No. 417,290.

This invention relates to electrostatically shielded transformer coil windings and method of making the same, and particularly to a method of winding or wrapping metallic shields in multiple about a plurality of electric coils as the same are built up on winding machines. v

An object of the invention is to provide a method of winding or wrapping in multiple a plurality of electric coils or helices simultaneously on a single body such as a tube, mandrel, spool or the like, and during the winding of such coils winding or wrapping into the same individual metallic shields for all of the coils, which individual metallic shields are connected together at the feed-in ends for manipulation as a single sheet.

Another object of the invention is to provide a novel method of applying metallic shields to electric coils while the same are I being wound.

A further object of the invention is to provide terminal strips which may be fastened to the tube, mandrel, spool or the like, or to any-part of the coil, in the manufacture of electrical coils suitable for transformers and the like, which terminal strips have integrally formed lugs to which the ends of the wires may be quickly fastened and about which the coils are wound in such manner as not to in- -terfere with the winding process or=--pro-' trude in any direction from the coils when finished.

A further object of the invention is to'provide a method of winding a plurality of metallic shield members about a'plurality of coils which are being simultaneously wound on a winding machine.

Another and further object of .theinvention is to provide a novel method of-applytrical coils being simultaneously wound which consists in' providing a plurality of individual shield members integrally connected at the feed-in ends so that the same functions as a sheet and when fed into the coils on the mandrel spool about which the same are being formed will be quickly wrapppeda'bout the individual coils and then when the mandrel, spool or tube is transversely cut to separate the several coils formed thereon, the cut ends of the shield will provide means for making electrical connection with the same.

A still further object of the invention is coils are separated, the shields being insulated except at such on connections may be made. v

The above, other and further objects of the t ends where electrical invention will be apparent from the following description, accompanying drawings and appended claims.

According to the invention, the method consists in forming from a single sheet of purposes a plurality of strips which are separated laterally but all of which are joined at one end, which end may serve as the feed-in end of the shield member. There are as many of the extensions or strips as there are separate coils to be wound on the mandrel, core, tube or spool- The common or connected portion is severed between every two of the several extensions as the mandrel, spool or tube is severed transversely to provide a plurality of separate coils. Exposed ends of the conmaterial suitable for electrostatic shielding nected portion of the shield element which now is severed provides means for making electrical connection with the shield if desired.

The invention contemplates a transformer having the primary and secondary windings separated by a metallic shield which is in-' serted by winding as the transformer coil is wound and which provides means for making electrical connection with the shield in the finished coil.

Embodiments of the invention are illustrated in the accompan ing drawings and the views thereof are as ollows:

Figure 1 is a fragmental isometric perspec tive view of a tube or mandrel about which a plurality of coils are formed in spaced zones and shows a terminal stri applied thereto and fragments of sheets insulating material and also fragments of the shield elements forming a part of and embodying the present invention. 7

Figure 2 is an isometric perspective view of a coil winding, with parts broken away to show details of construction, made in accordance with this invention.

Figure 3 is a view similar to Figure 2 and shows a pi -tail formed integrally with the shield mem er;

Figure 4 is a fragmental plan view of one form of shield member.

Figure is a fragmental plan 'view of anotherform of shield member showing a different way of making the same.

There is illustrated in Figure 1 a semi-diarammatic representation of a mechanism or winding simultaneously a plurality of coils in spaced zones on a mandrel, spool,

tube or the like designated generally at 1.

The mandrel 1 is supported at each end in a suitable winding machine in a manner to be driven by the winding machine as is well understood by-those skilled in the art.

a The mandrel or core 1 in the present instance is illustrated as being driven by a shaft 2 carrying a pulley 3 over which a belt 4 passes and which belt is driven in any suitable manner by means not shown. The inner end of the shaft 2 carries a lug 5 so shaped as to enter the end of the mandrel 1 and drive the same. A tail shaft 6 supports the other end of the mandrel 1.

The mandrel or core 1 may be made of any suitable material such as cardboard, paperboard or the like, and at the commencement of Winding or coiling is inserted in the winding machine in the manner illustrated in Figure 1.

A terminal strip 7 having a plurality of in tegrally formed lugs 8 is pasted or otherwise fastened along the mandrel 1 so that the ends of the wires, as many'as there may be, ma be quickly attached to the lugs by lifting the same from the plane of the strip 7 by the finger nail of the operator, whereupon the ends of the several wires are secured. The mandrel is then rotated and the wires wound about the same.

The shaft 2 is driven at considerable speed and suitable guide means not shown but well understood in the art direct the several Wires so as to form a plurality of helices on the mandrel 1 in spaced zones, thereby forming a plurality of coils on a single mandrel or core which later may be severed between the coils thus forming a plurality of electrical coils.

primary winding and the outer winding as the secondary. i

The mandrel 1 is rotated until the primary winding A has been built up with the proper number of turns and layers all of which layers are insulated one from another by insulating sheets 9 interposed between the several layers.

.After the primary windings have been completed and terminal strip 7 secured in place as shown on Figure 1 by being placed I under one or more turns of the outer layer of the primary windings, the ends of the primary wires are cut from the spools supplying the same and held in place by being wrapped around the lugs on the terminal stri -T e secondary windings are then connected to lugs on the-terminal strip in like manner.

One or more sheets of insulating material, together with the metallic shields, are wound into the coils and held in place by one or more turns of the secondary windings. The sheets of insulating material are so placed that they insulate under and over the metallic shield.

Figures 4 and 5 illustrate certain forms that the shield may take.

The form illustrated in Figure 4 includes a pluralit of shield portions 12 connected or integrafiy formed with a connecting portion 13. The portions 12 and 13 are fashioned by blanking a sheet of material of proper kind for the purpose intended, such as brass or the like, to provide a finished structure as that illustrated in Figure 4:. a

The width of the several portions 12 is substantially that of the width of a layer of wire winding or perhaps slightly less, and the length of the portions 12 may be made as desired so that when the connecting pory tion 13 is severed along the dotted lines 14,

the adjacent ends of the shield may overlap or may be slightly spaced as illustrated in Figure 2 by dotted lines.

The form of shield illustrated in Figure 5 includes a plurality of shielding portions 15 which are connected at each end by connecting parts 16 and 17 and which in addition have pig-tails 18 fashioned at the time the shield is blanked to provide the form illustrated in Figure 5. The shield element of Figure 5 is inserted in the same manner as that illustrated in Figure 4 with the portion 16 at the top of Figure 5 serving as the feed-in margin. The portions 16 and 17 are severed along the dotted lines 19 when the several coils are cut by cutting the mandrel 1 transversely.

Figure 2 illustrates a finished coil winding utilizing the shield elements of Figure 4: and indicating in dotted lines at C the position of the shield. The secondary winding B is therefore se arated from the primary winding A by t e shield D which includes one of the shield portions 12 and its connected ends 13. One corner 20 may be bent to serve. as means for making electrical connection with the shield D.

Figure 2 illustrates'also the sheets 10 and 11 of insulating inserted in the manner here tofore described. I

A transformer coil such as that illustrated in Figure 2 is made from a mandrel 1 having a plurality of helices or coils wound about the same in spaced zones and then severed between the zones, which line of severance is that indicated in the dotted lines 14 of Figure 4 and 19 of Figure 5.

Figure 3 illustrates a transformer winding utilizing the shield of Figure 5 which shows the primary winding A separated from the secondary winding B by shield E which includes one of the shield port-ions 15, a part of the end 16 and a part of the end 17. The pig tail 18 has been bent outwardly to serve as means for making electrical connection with the shield. A corner of the end 17 is shown as bent upwardly for making another electrical connection to the shield if desired.

There are as many portions 12 and 15 of the shield element as there are spaced helices or coils on themandrcl. 1

The shield portions illustrated in Figures 4 and 5 are made from any electrical conducting material preferably from sheet brass or copper blanked to provide the formations illustrated.

The shield elements are fed to the mandrel with the feed-in edges 13 or 16 foremost so that when the feed-in edges engage the mandrelthe portions 12 or 15 will be wound about the primary winding as illustrated in Figures 2 and 3.

tions 12 or 15 as there are to be coils or trans- When the secondary winding 13 has been completed after a sufiicient number of turns and layers have been formed with all of the layers insulated one from another by suitable insulating sheets 9, the mandrel 1. is removed from the machine and then cut transversely between the several coils or helices formed as described. v

It will be observedthat this invention provides for a quick and convenient manner of applying metallic shields tetransformer coil windings or similar electrical coils. The shields may be blanked from a single sheet of suitable material providing as'inany porformers formed, and then having these portions connected as described, the whole may be readily and quickly inserted in a winding machine and wound about the mandrel, leaving one of the portions 12 or one of the portions 15 as a shield between the windings for one of the helices or coils. The cutting of the mandrel 1 transversely between the coils also cuts the portions 13 or 16 and 17 of the shield element, thereby leaving exposed at the sides of the coils or transformers these shield portions to which electrical connection may be made if desired. 4

The invention makes possible more rapid formation of transformer coil windings in that it provides for the insertion of the shield elements as an integral unit with portions for every one of the helices or coils, which units are severed when the coils are severed from the mandrel.

It is believed that the invention has been sufliciently illustrated and described to enable those skilled in the art to which the same appertains to fully understand the same without having to illustrate a winding machine or other mechanical details.

The invention has been described herein more or less precisely as to details and it is thereby as changes may be made in the arrangement and proportion of parts and that equivalents may be substituted without departing from the spirit and scope of the invention. v

The invention is claimed as follows 1. The method of making electro-statically shielded transformer coils which consists in simultaneously winding a plurality of helices in a single layer in separated zones on a single body, then simultaneously winding a sheet of insulating material about said layer, then simultaneously winding another layer of the helices about the insulating sheet over the first layer, then simultaneously winding the second layer of the helices with a sheet of insulating material common to all, and thus continuing winding the desired number of layers, then applying a terminal strip having integrally formed lugs along the mandrel with one lug adjacent a helix, then winding a shield element having insulating material under and over same about the last layer so formed and said strip, said shield element having as many lateral extensions as there are helices, and then winding the second coil in the same manner as the first coil. I

v 2. An improvement in the method of producing electrostatically shielded coils in multiple which consists in the steps of cutting sheets of non-magnetic metallic material each into a plurality of laterally spaced extending strips integrally connected at one end, then wrapping said strips about a plurality of laterally spaced coil s on' a mandrel and then severing the mandrel and connecting end portions of said shields to provide separated coils thereby exposing the cut poriii) tions of the shields at the ends of the coils for connection purposes with the balance of the strips within the coils and away from the ends of the coils.

In testimony whereof I have hereunto subscribed my name at Chicago, Cook county Illinois.

W'HJMER J. LEIDY. 

